Microalgae in the wild often form consortia with other species promoting their own health and resource foraging opportunities. The recent application of microalgae cultivation and deployment in commercial photobioreactors (PBR) so far has focussed on single species of algae, resulting in multi-species consortia being largely unexplored. Reviewing the current status of PBR ecological habitat, this article argues in favor of further investigation into algal communication with conspecifics and interspecifics, including other strains of microalgae and bacteria. These mutualistic species form (...) the ‘phycosphere’: the micro-environment surrounding microalgal cells, potentiating the production of certain metabolites through biochemical interaction with cohabitating microorganisms. A better understanding of the phycosphere could lead to novel PBR configurations, capable of incorporating algal-microbial consortia, potentially proving more effective than single-species algal systems. (shrink)

Water plants of all sizes, from the 60-meter long Pacific Ocean giant kelp (Macrocystis pyrifera) to the micro ur-plant blue-green algae, deserve attention from critical plant studies. This is the first book in environmental humanities to approach algae, swimming across the sciences, humanities, and arts, to embody the mixed nature and collaborative identity of algae. Ranging from Medieval Islamic texts describing algae and their use, Japanese and Nordic cultural practices based in seaweed and algae, and (...) confronting the instrumentalization of seaweed to mitigate cow methane release and the hype of algal photobioreactors, amongst many other standpoints, this volume comprehensively addresses the ancestors of terrestrial plants through appreciating their unique aquatic medium. (shrink)

We live in a time where masks are rewriting wearable protocol. It is critical to understand entwining narratives around masks from the notion of health and safety to a wider discourse between the masked and the mask, including opportunistic capitalism and climatic implications. How about a mask that breathes, that is made by organic raw materials? As we confront and question narratives of the new normalcy in the year of pandemic and hindsight, these frames have coalesced in a vision of (...) the mask as an emblem for open-source eco-consciousness-functional, accessible DIY living wearables made with biomaterials. ‘Algae Mask’ explores the symbiosis between humans and other beings, layered as second skins; this project is driven by an ardent group of art and design practitioners across the Asia-Pacific and European regions with ongoing satellite collaborations. A related film Algae Dream, on the other hand, speculates on the prototyping process and the sleek languages of market economy to smudge the fine line between fiction and reality. Within the bricolage of source videos and original footages, motivational video mock-up and authentic presentation documentation, the video essay intends to challenge audience in a multiplicity of narrations stemming from discourses of business and science. (shrink)

The consideration of ‘mutual benefits’ and partner cooperation have long been the accepted standpoint from which to draw inference about the onset, maintenance and breakdown of the coral‐algae endosymbiosis. In this paper, I review recent research into the climate‐induced breakdown of this important symbiosis (namely ‘coral bleaching’) that challenges the validity of this long‐standing belief. Indeed, I introduce a more parsimonious explanation, in which the coral host exerts a ‘controlled parasitism’ over its algal symbionts that is akin to an (...) enforced domestication arrangement. Far from being pathogenic, a range of well‐established cellular processes are reviewed that support the role of the coral host as an active ‘farmer’ of the energy‐rich photoassimilates from its captive symbionts. Importantly, this new paradigm reposes the deleterious bleaching response in terms of an envelope of environmental conditions in which the exploitative and captive measures of the coral host are severely restricted. The ramification of this new paradigm for developing management strategies that may assist the evolution of bleaching resistance in corals is discussed. (shrink)

All disciplines must define their basic units and core processes. In evolutionary biology, the core process is natural selection and the basic unit of selection and adaptation is the individual. To operationalize the theory of natural selection we must count individuals, as they are the bearers of fitness. While canonical individuals have often been taken to be multicellular organisms, the hierarchy of life shows that new kinds of individuals have evolved. A variety of criteria have been used to define biological (...) individuality. Some criteria rely on the presence/absence of a particular property while others advocate an approach that reflects the process of natural selection. The plethora of approaches to classifying individuality has resulted in confusion regarding how to study individuality in a given taxon. (shrink)

The eyespot organelle of the green alga Chlamydomonas allows the cell to phototax toward (or away) from light to maximize the light intensity for photosynthesis and minimize photo‐damage. At cytokinesis, the eyespot is resorbed at the cleavage furrow and two new eyespots form in the daughter cells 180° from each other. The eyespots are positioned asymmetrically with respect to the microtubule cytoskeleton. Eyespots are assembled from all three chloroplast membranes and carotenoid‐filled granules, which form a sandwich structure overlaid by the (...) tightly apposed plasma membrane. This review describes (1) my interest in cellular asymmetry and organelle biology, (2) isolation of mutations that describe four genes governing eyespot placement and assembly, (3) the characterization of the EYE2 gene, which encodes a thioredoxin superfamily member, and (4) the characterization of the MIN1 gene, which is required for the layered organization of granules and membranes in the eyespot. BioEssays 25:410–416, 2003. © 2003 Wiley Periodicals, Inc. (shrink)

Adaptations can occur at different hierarchical levels (e.g., cells and multicellular organisms), but it can be difficult to identify the level(s) of adaptation in specific cases. A major problem is that selection at a lower level can filter up, creating the illusion of selection at a higher level. We use optimality modeling of the volvocine algae to explore the emergence of genuine group (i.e., colony-level) adaptations. We find that it is helpful to develop an explicit model for what group (...) fitness would be in the absence of group-level relationships between traits and group fitness. We call this “counterfactual fitness,” because in many actual cases of interest there are group-level relationships. Once counterfactual fitness is modeled, the difference between effects that filter up and genuine group selection is explicit and so, therefore, is the distinction between apparent and genuine group adaptations. We call the latter group-specific adaptations. Recognizing group-specific adaptations is important because only group-specific adaptations would cause the lower-level units (cells in this case) to be maladapted if they were to leave the group and enter a global cell-level population. Thus, as group-specific adaptations evolve, they create selective pressure for increased cohesiveness and individuality of groups. This article suggests that group-specific adaptations could be present in the simplest, earliest branching colonial volvocine species, which do not have distinct specialized cells. The article also makes predictions about the kind of empirical evidence needed to support or refute the hypothesis that a particular trait is a group-level adaptation. (shrink)

Historians and philosophers of twentieth-century life sciences have demonstrated that the choice of experimental organism can profoundly influence research fields, in ways that sometimes undermined the scientists’ original intentions. The present paper aims to enrich and broaden the scope of this literature by analysing the career of unicellular green algae of the genus Chlorella. They were introduced for the study of photosynthesis in 1919 by the German cell physiologist Otto H. Warburg, and they became the favourite research objects in (...) this field up to the 1960s. The paper argues that dealing with Chlorella’s high metabolic flexibility was crucial for the emergence of a new conception of photosynthesis, as a plastic, integrated system of pathways. At the same time, it led to new collaborations between physiologists and phycologists, both of whom started to re-orient their studies in ecologically informed directions. Following Chlorella’s trail, hence, not only elucidates how experimental organisms forced scientists to change their conceptual approaches and techniques, but also provides insight into the interaction of different lines of research of mid-twentieth century plant sciences. (shrink)

While women’s participation at research stations has been celebrated as a success story for women in science, their experiences were not quite equal to that of men scientists. This article shows how women interested in practicing marine science at research institutions experienced different living and research environments than their male peers; moreover, it illustrates how those gendered experiences reflected and informed the nature of their scientific practices and ideas. Set in Roscoff, France, this article excavates the work and social worlds (...) of a Russian scientist, Natalie Karsakoff (1863–1941), and a British émigré in France, Anna Vickers (1853–1906), to show how a small group of single women who studied algae created a “central bureau of feminine algology.” The social aspects of this bureau, and the physical space and support funded by Vickers, allowed these women scientists to both participate in male-dominated practices of science and lend evidentiary support to an ecological category that emphasized benign coexistence rather than struggle. This study adds an empirical case of single women scientists managing successful careers in science and contributing to science through publication and research. (shrink)

Around the turn of the twentieth century, microbiologists in Western Europe and North America began to organize centralized collections of microbial cultures. Collectors published lists of the strains they cultured, offering to send duplicates to colleagues near and far. This essay explores the history of microbial culture collections through two cases: Johanna Westerdijk’s collection of phytopathogenic fungi in the Netherlands and Ernst Georg Pringsheim’s collection of single-celled algae at the German University in Prague. Historians of science have tended to (...) look at twentieth-century biological specimen collections as either repositories of communal research materials or storehouses of economically important biological variation. An examination of Westerdijk’s and Pringsheim’s collections illustrates how collectors, researchers, and patrons ascribed different kinds of value to collections featuring distinctive microbial life forms. This essay argues that characteristics of cultivated microorganisms, such as a fungus’s propensity to infect crops or an alga’s amenability to experimentation, shaped the trajectories of Westerdijk’s and Pringsheim’s collections as these collectors developed relationships with colleagues and patrons. Letters between Westerdijk and Pringsheim open a window onto divergences in their approaches to collecting cultures, while also shedding light on the aspirational internationality of the collections that resulted. (shrink)

The cytoskeleton has a central role in eukaryotic biology, enabling cells to organize internally, polarize, and translocate. Studying cytoskeletal machinery across the tree of life can identify common elements, illuminate fundamental mechanisms, and provide insight into processes specific to less‐characterized organisms. Red algae represent an ancient lineage that is diverse, ecologically significant, and biomedically relevant. Recent genomic analysis shows that red algae have a surprising paucity of cytoskeletal elements, particularly molecular motors. Here, we review the genomic and cell (...) biological evidence and propose testable models of how red algal cells might perform processes including cell motility, cytokinesis, intracellular transport, and secretion, given their reduced cytoskeletons. In addition to enhancing understanding of red algae and lineages that evolved from red algal endosymbioses (e.g., apicomplexan parasites), these ideas may also provide insight into cytoskeletal processes in animal cells. (shrink)

In this work a mechanistic explanation of the classical algae growth model built by M. R. Droop in the late sixties is proposed. We first recall the history of the construction of the “predictive” variable yield Droop model as well as the meaning of the introduced cell quota. We then introduce some theoretical hypotheses on the biological phenomena involved in nutrient storage by the algae that lead us to a “conceptual” model. Though more complex than Droop’s one, our (...) model remains accessible to a complete mathematical study: its confrontation to the Droop model shows both have the same asymptotic behavior. However, while Droop’s cell quota comes from experimental bio-chemical measurements not related to intra-cellular biological phenomena, its analogous in our model directly follows our theoretical hypotheses. This new model should then be looked at as a re-interpretation of Droop’s work from a theoretical biologist’s point of view. (shrink)

Algae are significant members of Earth's biodiversity. Having been studied for a long time, the discovery of new algal phyla is extremely unusual. Recently, the enigmatic “Picobiliphyta,” a group of uncultured eukaryotes unveiled using molecular tools, were claimed to represent an unrecognized early branching algal lineage with a nucleomorph (remnant nucleus of a secondary algal endosymbiont) in their plastids. However, subsequent studies rejected the presence of a nucleomorph, and single‐cell genomic studies failed to detect any plastid‐related genes, ruling out (...) the possibility of plastid occurrence. The isolation of the first “picobiliphyte,” Picomonas judraskeda, a tiny organism that feeds on very small (<150 nm) organic particles, came as final proof of their non‐photosynthetic lifestyle. Consequently, the group has been renamed Picozoa. The passage from “picobiliphytes” to “picozoa” illustrates the crucial role that classical protistology should play to provide sound biological context for the wealth of data produced by modern molecular techniques. (shrink)

Recent data have provided evidence for an unrecognised ancient lineage of green plants that persists in marine deep-water environments. The green plants are a major group of photosynthetic eukaryotes that have played a prominent role in the global ecosystem for millions of years. A schism early in their evolution gave rise to two major lineages, one of which diversified in the world's oceans and gave rise to a large diversity of marine and freshwater green algae (Chlorophyta) while the other (...) gave rise to a diverse array of freshwater green algae and the land plants (Streptophyta). It is generally believed that the earliest-diverging Chlorophyta were motile planktonic unicellular organisms, but the discovery of an ancient group of deep-water seaweeds has challenged our understanding of the basal branches of the green plant phylogeny. In this review, we discuss current insights into the origin and diversification of the green plant lineage. (shrink)

Biologists have long theorized about the evolution of life cycles, meiosis, and sexual reproduction. We revisit these topics and propose that the fundamental difference between life cycles is where and when multicellularity is expressed. We develop a scenario to explain the evolutionary transition from the life cycle of a unicellular organism to one in which multicellularity is expressed in either the haploid or diploid phase, or both. We propose further that meiosis might have evolved as a mechanism to correct for (...) spontaneous whole‐genome duplication (auto‐polyploidy) and thus before the evolution of sexual reproduction sensu stricto (i.e. the formation of a diploid zygote via the fusion of haploid gametes) in the major eukaryotic clades. In addition, we propose, as others have, that sexual reproduction, which predominates in all eukaryotic clades, has many different advantages among which is that it produces variability among offspring and thus reduces sibling competition. (shrink)

The photosynthetic organelle of algae and plants (the plastid) traces its origin to a primary endosymbiotic event in which a previously non‐photosynthetic protist engulfed and enslaved a cyanobacterium. This eukaryote then gave rise to the red, green and glaucophyte algae. However, many algal lineages, such as the chlorophyll c‐containing chromists, have a more complicated evolutionary history involving a secondary endosymbiotic event, in which a protist engulfed an existing eukaryotic alga (in this case, a red alga). Chromists such as (...) diatoms and kelps then rose to great importance in aquatic habitats. Another algal group, the dinoflagellates, has undergone tertiary (engulfment of a secondary plastid) and even quaternary endosymbioses. In this review, we examine algal diversity and show endosymbiosis to be a major force in algal evolution. This area of research has advanced rapidly and long‐standing issues such as the chromalveolate hypothesis and the extent of endosymbiotic gene transfer have recently been clarified. BioEssays 26:50–60, 2004. © 2003 Wiley Periodicals, Inc. (shrink)

Vibrant Death links philosophy and poetry-based, corpo-affectively grounded knowledge seeking. It offers a radically new materialist theory of death, critically moving the philosophical argument beyond Christian and secular-mechanistic understandings. The book's ethico-political figuration of vibrant death is shaped through a pluriversal conversation between Deleuzean philosophy, neo-vitalist materialism and the spiritual materialism of decolonial, queerfeminist poet and scholar Gloria Anzaldua. The book's posthuman deexceptionalizing of human death unfurls together with a collection of poetry, and autobiographical stories. They are analysed through the (...) lens of a posthuman, queerfeminist revision of the method of autophenomenography (phenomenological analysis of autobiographical material). Nina Lykke explores the speaking position of a mourning, queerfeminine "I", who contemplates the relationship with her dead beloved lesbian life partner. She reflects on her enactment of processes of co-becoming with the phenomenal and material traces of the deceased body, and the new assemblages with which it has merged through death's material metamorphoses: becoming-ashes through cremation, and becoming-mixed-with-algae-sand when the ashes were scattered across a seabed made of fiftyfive million-year-old, fossilized algae. It is argued that the mourning "I"'s intimate bodily empathizing (theorized as symphysizing) with her deceased, queermasculine beloved life partner facilitates the processes of vitalist-material and spiritual-material co-becoming, and the rethinking of death from a new and different perspective than that of the sovereign, philosophical subject. (shrink)

Ethnobotanical research provides ample justification for comparing diverse biological nomenclatures and exploring ways that retain alternative naming practices. However, how (and whether) comparison of nomenclatures is possible remains a subject of discussion. The comparison of diverse nomenclatural practices introduces a suite of epistemic and ontological difficulties and considerations. Different nomenclatures may depend on whether the communities using them rely on formalized naming conventions; cultural or spiritual valuations; or worldviews. Because of this, some argue that the different naming practices may not (...) be comparable if the ontological commitments employed differ. Comparisons between different nomenclatures cannot assume that either the naming practices or the object to which these names are intended to apply identifies some universally agreed upon object of interest. Investigating this suite of philosophical problems, I explore the role grey nomenclatures play in classification. ‘Grey nomenclatures’ are defined as those that employ names that are either intentionally or accidentally non-Linnaean. The classification of the lichen thallus (a symbiont) has been classified outside the Linnaean system by botanists relying on the International Code of Nomenclature for algae, fungi, and plants (ICN). But, I argue, the use of grey names is not isolated and does not occur exclusively within institutionalized naming practices. I suggest, ‘grey names’ also aptly describe nomenclatures employed by indigenous communities such as the Samí of Northern Finmark, the Sherpa of Nepal, and the Okanagan First Nations. I pay particular attention to how naming practices are employed in these communities; what ontological commitments they hold; for what purposes are these names used; and what anchors the community’s nomenclatural practices. Exploring the history of lichen naming and early ethnolichenological research, I then investigate the stakes that must be considered for any attempt to preserve, retain, integrate, or compare the knowledge contained in both academically formalized grey names and indigenous nomenclatures in a way that preserves their source-specific informational content. (shrink)

Coral reefs provide substantial benefits to humans by generating biologically diverse ecosystems and reducing coastal hazards. However, in recent years, mass mortality of coral reefs due to bleaching has been witnessed in the ocean worldwide. Bleaching induced by the loss of the symbiotic relationship between algae and coral is mainly attributed to climate change. Marine protected areas (MPAs) can effectively prevent local disturbances but are less likely to conserve the coral reefs from global events like climate change. Other conservation (...) and restoration methods can be useful to protect and replenish the coral population temporarily, but whether they are feasible as sustainable conservation strategies is still equivocal. Coral reef mass mortality is not an exceptional occurrence but is linked to various instances of ecological loss, serving as an S.O.S. signal of severe prolonged climate extremes. (shrink)

The research focused on the cross-boundary impacts of ecological changes on the livelihood of communities in three villages in Stung Treng province, Cambodia. The research objectives were to analyze river ecological changes and their drivers, and to explore the impacts of these changes on the livelihood of the communities. The research was conducted in Kraom, Kaoh Snaeng, and Tonsang villages. The study found that there have been significant changes in the environment of these villages. The fishery resources have declined between (...) 2019 and 2022 due to factors such as population growth, illegal fishing, loss of flooded forests, and the presence of hydropower dams. The extent of flooded forests has also significantly decreased, negatively impacting fish populations and the overall ecosystem. Water level fluctuations have become irregular since 2018, with lower water levels during the rainy season compared to previous years. Riverbank landslides have been a concern, posing threats to safety and livelihoods. Excessive algae growth in the rivers has also been observed. The research findings indicate a decline in income from fish catch in all three villages, with varying levels of stability. Expenses for food have also varied. Migration patterns have been observed, with individuals seeking better opportunities elsewhere due to the decline in fish stocks. Crop damages have been attributed to irregular flooding and fluctuating water levels, leading to a decrease in crop cultivation. Changes in water quality, including the presence of lime and algae, have impacted the well-being of the residents. Overall, the research highlights the need for interventions and support to address the economic challenges faced by the communities, mitigate the loss of equipment and housing, and improve water quality. (shrink)

The fitness of any evolutionary unit can be understood in terms of its two basic components: fecundity (reproduction) and viability (survival). Trade-offs between these fitness components drive the evolution of life-history traits in extant multicellular organisms. We argue that these trade-offs gain special significance during the transition from unicellular to multicellular life. In particular, the evolution of germ–soma specialization and the emergence of individuality at the cell group (or organism) level are also consequences of trade-offs between the two basic fitness (...) components, or so we argue using a multilevel selection approach. During the origin of multicellularity, we study how the group trade-offs between viability and fecundity are initially determined by the cell level trade-offs, but as the transition proceeds, the fitness trade-offs at the group level depart from those at the cell level. We predict that these trade-offs begin with concave curvature in single-celled organisms but become increasingly convex as group size increases in multicellular organisms. We argue that the increasingly convex curvature of the trade-off function is driven by the cost of reproduction which increases as group size increases. We consider aspects of the biology of the volvocine green algae – which contain both unicellular and multicellular members – to illustrate the principles and conclusions discussed. (shrink)

The cryptomonads and chlorarachniophytes are two unicellular algal lineages with complex cellular structures and fascinating evolutionary histories. Both groups acquired their photosynthetic abilities through the assimilation of eukaryotic endosymbionts. As a result, they possess two distinct cytosolic compartments and four genomes—two nuclear genomes, an endosymbiont‐derived plastid genome and a mitochondrial genome derived from the host cell. Like mitochondrial and plastid genomes, the genome of the endosymbiont nucleus, or ‘nucleomorph’, of cryptomonad and chlorarachniophyte cells has been greatly reduced through the combined (...) effects of gene loss and intracellular gene transfer. This article focuses on the structure, function, origin and evolution of cryptomonad and chlorarachniophyte nucleomorph genomes in light of recent comparisons of genome sequence data from both groups. It is now possible to speculate on the reasons that nucleomorphs persist in cryptomonads and chlorarachniophytes but have been lost in all other algae with plastids of secondary endosymbiotic origin. BioEssays 29:392–402, 2007. © 2007 Wiley Periodicals, Inc. (shrink)

In recent decades, historians have become increasingly interested in the logistical challenges and difficulties encountered by those responsible for the collection, preservation and safe transport of specimens from the field to the museum or laboratory. This article builds on this trend by looking beyond apparent successes to consider the practices and practicalities of shipboard travel and maritime and coastal collecting activities. The discussion focuses on the example of William Henry Harvey, who travelled to Australia in pursuit of cryptogams – non-flowering (...) plants like mosses, lichens and algae – in 1853. In his private correspondence to family and friends, Harvey offered insights into the challenges and obstacles faced by all collectors in the period. His experiences were fundamentally shaped by the material culture, embodied knowledge and physical constraints he encountered on the way. On one level, shipboard and onshore collecting activities were facilitated by the connections forged by new technologies and Britain's global empire. But they also depended on specific contexts and relied on local agents and actors, as well as on the physical and technical facilities (and limitations) of those doing the collecting. The examples of Harvey and others shed light on the real, ‘lived’ experiences of individual collectors, the difficulties and challenges they encountered in amassing their collections, and the networks of people on which they relied. (shrink)

A central goal of philosophy of perception is to uncover the nature of sensory capacities. Ideally, we would like an account that specifies what conditions need to be met in order for an organism to count as having the capacity to sense or perceive its environment. And on the assumption that sensory states are the kinds of things that can be accurate or inaccurate, a further goal of philosophy of perception is to identify the accuracy conditions for sensory states. In (...) this paper I recommend a novel approach to these core issues, one that draws heavily on game-theoretic treatments of signaling in nature. A benefit of the approach is that it helps us to understand why biologists attribute sensory powers to such a diverse range of organisms, including plants, fungi, and algae. (shrink)

In contrast to vertical gene transfer from parent to offspring, horizontal (or lateral) gene transfer moves genetic information between different species. Bacteria and archaea often adapt through horizontal gene transfer. Recent analyses indicate that eukaryotic genomes, too, have acquired numerous genes via horizontal transfer from prokaryotes and other lineages. Based on this we raise the hypothesis that horizontally acquired genes may have contributed more to adaptive evolution of eukaryotes than previously assumed. Current candidate sets of horizontally acquired eukaryotic genes may (...) just be the tip of an iceberg. We have recently shown that adaptation of the thermoacidophilic red algaGaldieria sulphurariato its hot, acid, toxic‐metal laden, volcanic environment was facilitated by the acquisition of numerous genes from extremophile bacteria and archaea. Other recently published examples of horizontal acquisitions involved in adaptation include ice‐binding proteins in marine algae, enzymes for carotenoid biosynthesis in aphids, and genes involved in fungal metabolism.Editor's suggested further reading in BioEssaysJumping the fine LINE between species: Horizontal transfer of transposable elements in animals catalyses genome evolution Abstract. (shrink)

Introduction: working together on individuality / Lynn K. Nyhart and Scott Lidgard -- The work of biological individuality: concepts and contexts / Scott Lidgard and Lynn K. Nyhart -- Cells, colonies, and clones: individuality in the volvocine algae / Matthew D. Herron -- Individuality and the control of life cycles / Beckett Sterner -- Discovering the ties that bind: cell-cell communication and the development of cell sociology / Andrew S. Reynolds -- Alternation of generations and individuality, 1851 / Lynn (...) K. Nyhart and Scott Lidgard -- Spencer's evolutionary entanglement: from liminal individuals to implicit collectivities / Snait Gissis -- Biological individuality and enkapsis: from Martin Heidenhain's synthesiology to the völkisch national community / Olivier Rieppel -- Parasitology, zoology, and society in France, ca. 1880-1920 / Michael A. Osborne -- Metabolism, autonomy, and individuality / Hannah Landecker -- Bodily parts in the structure-function dialectic / Ingo Brigandt -- Commentaries: historical, biological, and philosophical perspectives -- Distrust that particular intuition: resilient essentialisms and empirical challenges in the history of biological individuality / James Elwick -- Biological individuality: a relational reading / Scott F. Gilbert -- Philosophical dimensions of individuality / Alan C. Love and Ingo Brigandt. (shrink)

The tropical lowlands of southern Mexico and Central America are composed of a complex mosaic of landscapes that presented a variety of possibilities and challenges to the subsistence practices of the ancient Maya. The Yalahau Regional Human Ecology Project has been investigating ancient Maya agricultural practices and use of resources in a unique fresh-water wetland zone located in the northeast corner of the Yucatán Peninsula. While containing only a sparse population today, the Yalahau region once supported numerous Maya communities and (...) civic-ceremonial centers, particularly during the Late Preclassic and Early Classic periods, between approximately 100 B.C. and A.D. 450. Our investigations have developed evidence that the ancient Maya manipulated and cultivated the wetland landscape of the region, used soil or algae from the wetlands to enrich upland garden plots, and cultivated trees within their communities. We suggest that the study of ancient Maya agricultural practices can contribute to sustainable development of the area today and in the future. (shrink)

This chapter combines formal models of how the fitness of a collective can become decoupled from the fitness with more empirical work on the volvocine algae. It uses the Volvox clade as a model system. It describes the evolution of altruism in the volvocine green algae. This chapter suggests that altruism may evolve from genes involved in life-history trade-offs. It shows the several cooperation, conflict, and conflict mediation cycles in the volvocine green algae. This cycle of cooperation, (...) conflict, and conflict mediation drives evolutionary transitions in individuality. (shrink)

Written for non-experts, this volume introduces the mechanisms that underlie reticulate evolution. Chapters are either accompanied with glossaries that explain new terminology or timelines that position pioneering scholars and their major discoveries in their historical contexts. The contributing authors outline the history and original context of discovery of symbiosis, symbiogenesis, lateral gene transfer, hybridization or divergence with gene flow, and infectious heredity. By applying key insights from the areas of molecular (phylo)genetics, microbiology, virology, ecology, systematics, immunology, epidemiology and computational science, (...) they demonstrate how reticulate evolution impacts successful survival, fitness and speciation. Reticulate evolution brings forth a challenge to the standard Neo-Darwinian framework, which defines life as the outcome of bifurcation and ramification patterns brought forth by the vertical mechanism of natural selection. Reticulate evolution puts forward a pattern in the tree of life that is characterized by horizontal mergings and lineage crossings induced by symbiosis, symbiogenesis, lateral gene transfer, hybridization or divergence with gene flow, and infective heredity, making the “tree of life” look more like a “web of life.” On an epistemological level, the various means by which hereditary material can be transferred horizontally challenges our classic notions of units and levels of evolution, fitness, modes of transmission, linearity, communities, and biological individuality. The case studies presented examine topics including the origin of the eukaryotic cell and its organelles through symbiogenesis; the origin of algae through primary and secondary symbiosis and dinoflagellates through tertiary symbiosis; the superorganism and holobiont as units of evolution; how endosymbiosis induces speciation in multicellular life forms; transferrable and non-transferrable plasmids and how they symbiotically interact with their host; the means by which pro- and eukaryotic organisms transfer genes laterally (bacterial transformation, transduction and conjugation as well as transposons and other mobile genetic elements); hybridization and divergence with gene flow in sexually-reproducing individuals; current (human) microbiome and viriome studies that impact our knowledge concerning the evolution of organismal health and acquired immunity; and how symbiosis and symbiogenesis can be modelled in computational evolution. (shrink)

While unicellular microbes such as phytoplankton (marine algae) have long been considered immortal unless eaten by predators, recent research suggests that under specific conditions entire populations of phytoplankton actively kill themselves; their assumed atemporality is being revised as marine ecologists recognize phytoplankton’s important role in the global carbon cycle. Drawing on empirical research into programmed cell death in marine microbes, this article explores how, in their study of microbial death, scientists change not only our understanding of microbial temporality, but (...) also reconstruct the relationship between life and death, biological individuality and assumptions about a natural teleology associated with bounded biological systems and genetic programmes. Reading this research together with a Derridean deconstruction of the limit between human and other animals with respect to death, this article explores how the deconstruction of individuality from within biology may suggest alternatives to our anthropocentric notion of time and embodiment. (shrink)

The recent discovery of microRNAs (miRNAs) in unicellular eukaryotes, including miRNAs known previously only from animals or plants, implies that miRNAs have a deep evolutionary history among eukaryotes. This contrasts with the prevailing view that miRNAs evolved convergently in animals and plants. We re‐evaluate the evidence and find that none of the 73 plant and animal miRNAs described from protists meet the required criteria for miRNA annotation and, by implication, animals and plants did not acquire any of their respective miRNA (...) genes from the crown ancestor of eukaryotes. Furthermore, of the 159 novel miRNAs previously identified among the seven species of unicellular protists examined, only 28 from the algae Ectocarpus and Chlamydomonas, meet the criteria for miRNA annotation. Therefore, at present only five groups of eukaryotes are known to possess miRNAs, indicating that miRNAs have evolved independently within eukaryotes through exaptation of their shared inherited RNAi machinery. (shrink)

While seeking novel food sources to feed the increasing population of the globe, several alternatives have been discussed, including algae, fungi or in vitro meat. The increasingly propagated usage of farmed insects for human nutrition raises issues regarding food safety, consumer information and animal protection. In line with law, insects like any other animals must not be reared or manipulated in a way that inflicts unnecessary pain, distress or harm on them. Currently, there is a great need for research (...) in the area of insect welfare, especially regarding species-specific needs, health, farming systems and humane methods of killing. Recent results from neurophysiological, neuroanatomical and behavioral sciences prompt caution when denying consciousness and therefore the likelihood of presence of pain and suffering or something closely related to it to insects. From an animal protection point of view, these issues should be satisfyingly solved before propagating and establishing intensive husbandry systems for insects as a new type of mini-livestock factory farming. (shrink)

N6‐methyladenine (6mA) is one of the most abundant types of DNA methylation, and plays an important role in bacteria; however, its roles in higher eukaryotes, such as plants, insects, and mammals, have been considered less important. Recent studies highlight that 6mA does indeed occur, and that it plays an important role in eukaryotes, such as worm, fly, and green algae, and thus the regulation of 6mA has emerged as a novel epigenetic mechanism in higher eukaryotes. Despite this intriguing development, (...) a number of important issues regarding its biological roles are yet to be addressed. In this review, we focus on the 5mC and 6mA modifications in terms of their production, distribution, and the erasure of 6mA in higher eukaryotes including mammals. We perform an analysis of the potential functions of 6mA, hence widening understanding of this new epigenetic mark in higher eukaryotes, and suggesting future studies in this field. (shrink)

Mentorship and collaboration necessarily shaped opportunities for women in science, especially in the late nineteenth century at rapidly expanding public co-educational universities. A few male faculty made space for women to establish their own research programs and professional identities. At the University of Minnesota, botanist Conway MacMillan, an ambitious young department chair, provided a qualified mentorship to Josephine Tilden. He encouraged her research on algae and relied on her to do departmental support tasks even as he persuaded the administration (...) to move her from instructor to assistant professor in 1903. Resulting publications on Minnesota algae led her to look further west, first at Yellowstone National Park and then along the Pacific Northwest coast. After visiting a particularly productive littoral site on Vancouver Island, she suggested that they establish a Minnesota Seaside Station there. Over its seven years in operation under the Midwestern leaders, that location proved remarkably productive. At the remote site, the two operated within their typical but not inevitable gendered roles and deliberately defined their seaside station as unconventional. They expected participants to study productively and, at the same time, find imaginative ways to enjoy nature at a place far from urban amenities. Gendered expectations remained casual as participants moved both within and against them. This study investigates how, in the early twentieth century, the role and expectations of mentorship shifted as Tilden established her own independent research agenda. The Minnesota Seaside Station, in particular, proved significant in developing the leadership skills essential for her to pursue research in the Pacific region at a time when American expansionism and indigenous cooperation made sites accessible to academic researchers. (shrink)

Many pigmented heterokonts are able to synthesize elements of their cell walls (the frustules) of dense biogenic silica. These include diatom algae, which occupy a significant place in the biosphere. The siliceous frustules of diatoms have species‐specific patterns of surface structures between 10 and a few hundred nanometers. The present review considers possible mechanisms of uptake of silicic acid from the aquatic environment, its transport across the plasmalemma, and intracellular transport and deposition of silica inside the specialized Silica Deposition (...) Vesicle (SDV) where elements of the new frustule are formed. It is proposed that a complex of silicic acid with positively charged proteins silaffins and polypropylamines remains a homogeneous solution during the intracellular transport to SDV, where biogenic silica precipitates. The high density of the deposited biogenic silica may be due to removal of water from the SDV by aquaporins followed by syneresis—a process during which pore water is expelled from the network of the contracting gel. The pattern of aquaporins in the silicalemma, the membrane embracing the SDV, can determine the pattern of species‐specific siliceous nanostructures. BioEssays 30:328–337, 2008. © 2008 Wiley Periodicals, Inc. (shrink)

Communication is defined as an interaction between at least two living agents which share a repertoire of signs. These are combined according to syntactic, semantic and context dependent, pragmatic rules in order to coordinate behavior. This volume deals with the important roles of soil bacteria in parasitic and symbiotic interactions with viruses, plants, animals and fungi. Starting with a general overview of the key levels of communication between bacteria, further reviews examine the various aspects of intracellular as well as intercellular (...) biocommunication between soil microorganisms. Th is includes the various levels of biocommunication between phages and bacteria, between soil algae and bacteria, and between bacteria, fungi and plants in the rhizosphere, the role of plasmids and transposons, horizontal gene transfer, quorum sensing and quorum quenching, bacterial-host cohabitation, phage-mediated genetic exchange and soil viral ecology. (shrink)

It has recently emerged that malarial, toxoplasmodial and related parasites contain a vestigial plastid (the organelle in which photosynthesis occurs in plants and algae). The function of the plastid in these obligate intracellular parasites has not been established. It seems likely that modern apicomplexans derive from photosynthetic predecessors, which perhaps formed associations with protists and invertebrates and abandoned autotrophy in favour of parasitism. Recognition of a third genetic compartment in these parasites proffers alternative strategies for combating a host of (...) important human and animal diseases. It also poses some fascinating questions about the evolutionary biology of this important group of pathogens. (shrink)